I have my old SCII client running good in Windows Vista 32/64bits and follow the instructions of the page http://www.uvnc.com/pchelpware/sc/creator.html and upload the old client and create the SCIII with success.
Tested in a machine with Windows 7 32 and use the UltraVNC Viewer (Listen Mode Encrypt), with 1.0.5 Win32 version. I put my rc4.key from the client in the directory of c:\program files\ultravnc, but didnÂ´t works.
I do the same test with the last version of the UltraVNC without any success.

My new client SCIII runs well from another machines with windows 7, vista, XP connecting to a Windows Vista or windows XP to my principal machine (server VNC) with Vista 64bits.